I know there are some folks here that have considerable experience with high
speed parts and lubricating oils.
I anyone has recommendations for oils with properties suitable for high
speed bearings, I'd appreciate hearing them.

The spindle speeds in toolpost grinders can range from about 6k to 30k RPM.

I haven't taken them apart to see exactly what types of bearings are used in
the spindles, but I would expect them to be high precision ball bearing
assemblies. I've seen parts list prices of over $200 each for bearings with
ODs of about 1.25".

I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html

Bill,
I just sent a unit back to Dumore for overhaul, as the shaft and bearing
assembly is pretty special and is balanced at the factory. At least my
grinder is sealed and no lubrication is required. My bill was around $350
all in. I didn't think that was too bad. I'm not sure this is a lot of help,
but more, I don't know. Perhaps calling them on the phone would be useful,
they were very friendly and helpful when I spoke with them
Steve

"Wild_Bill" wrote in message
...
I know there are some folks here that have considerable experience with
high speed parts and lubricating oils.
I anyone has recommendations for oils with properties suitable for high
speed bearings, I'd appreciate hearing them.

The spindle speeds in toolpost grinders can range from about 6k to 30k
RPM.

I haven't taken them apart to see exactly what types of bearings are used
in the spindles, but I would expect them to be high precision ball bearing
assemblies. I've seen parts list prices of over $200 each for bearings
with ODs of about 1.25".

I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html

Thanks Steve, I didn't notice any Dumore models that weren't serviceable (in
looking thru their various models), but I did see their recommendation to
return their motors for servicing.

These grinder's parts would need to be made up of specialized parts for the
speeds they operate at, and I'd suppose that many used ones don't operate as
well as they were intended to.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Steve Lusardi" wrote in message
...
Bill,
I just sent a unit back to Dumore for overhaul, as the shaft and bearing
assembly is pretty special and is balanced at the factory. At least my
grinder is sealed and no lubrication is required. My bill was around $350
all in. I didn't think that was too bad. I'm not sure this is a lot of
help, but more, I don't know. Perhaps calling them on the phone would be
useful, they were very friendly and helpful when I spoke with them
Steve

"Wild_Bill" wrote in message
...
I know there are some folks here that have considerable experience with
high speed parts and lubricating oils.
I anyone has recommendations for oils with properties suitable for high
speed bearings, I'd appreciate hearing them.

The spindle speeds in toolpost grinders can range from about 6k to 30k
RPM.

I haven't taken them apart to see exactly what types of bearings are used
in the spindles, but I would expect them to be high precision ball
bearing assemblies. I've seen parts list prices of over $200 each for
bearings with ODs of about 1.25".

I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html

Bill,
If the spindle assembly is not up to snuff, you see harmonic patterns in the
finish. I think it's cheaper to leave it to the experts to sort out. My last
experience was with a small unit that I bought used. It looked like new, but
when I tested it, there was an inperceptable vibration and this could be
seen in the finish. When I sent it back, I was told that there had been an
engineering change in the design, which they applied to my unit at the same
time. If I had had not sent it back, I would not of known. It now works
perfectly.
Steve

"Wild_Bill" wrote in message
...
Thanks Steve, I didn't notice any Dumore models that weren't serviceable
(in looking thru their various models), but I did see their recommendation
to return their motors for servicing.

These grinder's parts would need to be made up of specialized parts for
the speeds they operate at, and I'd suppose that many used ones don't
operate as well as they were intended to.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html


"Steve Lusardi" wrote in message
...
Bill,
I just sent a unit back to Dumore for overhaul, as the shaft and bearing
assembly is pretty special and is balanced at the factory. At least my
grinder is sealed and no lubrication is required. My bill was around $350
all in. I didn't think that was too bad. I'm not sure this is a lot of
help, but more, I don't know. Perhaps calling them on the phone would be
useful, they were very friendly and helpful when I spoke with them
Steve

"Wild_Bill" wrote in message
...
I know there are some folks here that have considerable experience with
high speed parts and lubricating oils.
I anyone has recommendations for oils with properties suitable for high
speed bearings, I'd appreciate hearing them.

The spindle speeds in toolpost grinders can range from about 6k to 30k
RPM.

I haven't taken them apart to see exactly what types of bearings are
used in the spindles, but I would expect them to be high precision ball
bearing assemblies. I've seen parts list prices of over $200 each for
bearings with ODs of about 1.25".

I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.

--
WB
.........
metalworking projects
www.kwagmire.com/metal_proj.html

On Sun, 21 Dec 2008 23:38:22 -0500, "Wild_Bill"
wrote:

I know there are some folks here that have considerable experience with high
speed parts and lubricating oils.
I anyone has recommendations for oils with properties suitable for high
speed bearings, I'd appreciate hearing them.

The spindle speeds in toolpost grinders can range from about 6k to 30k RPM.

I haven't taken them apart to see exactly what types of bearings are used in
the spindles, but I would expect them to be high precision ball bearing
assemblies. I've seen parts list prices of over $200 each for bearings with
ODs of about 1.25".

I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.


At those speeds, most bearings will be running with air/oil misting and
a very light turbine oil such as DTE Light

Cavitation becomes a real problem at high speeds in oil baths, as does
the fact that oil isnt a compressible and too much tends to make the
balls in the race ride up and over the oil droplets, slamming back down
on the other side.

The same effect that makes potholes on the back side of speed bumps.

Gunner

"They couldn't hit an elephant at this dist..."
Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania

On Sun, 21 Dec 2008 23:38:22 -0500, "Wild_Bill"
wrote:

The spindle speeds in toolpost grinders can range from about 6k to 30k RPM.

I haven't taken them apart to see exactly what types of bearings are used in
the spindles, but I would expect them to be high precision ball bearing
assemblies. I've seen parts list prices of over $200 each for bearings with
ODs of about 1.25".

A $6 6001 (12 x 28mm) bearing is rated for 26KRPM grease lubed and 32K
in oil. Oil mist or oil spot lube will probably push that to 45K. But
the devil is in the details of the spindle's construction at those
speeds. What you get with a $200 bearing is not necessarily higher
speed, but closer tolerances on the bearing's dimensions and running
accuracy.

--
Ned Simmons

Gunner Asch wrote:

At those speeds, most bearings will be running with air/oil misting and
a very light turbine oil such as DTE Light

Our Okuma grinders use DTE Light and air mist. Looks like ceramic balls and phenolic
cages. 30K spindles. 3HP or so.

Wes

On Tue, 23 Dec 2008 20:18:49 -0500, Wes wrote:

Gunner Asch wrote:

At those speeds, most bearings will be running with air/oil misting and
a very light turbine oil such as DTE Light

Our Okuma grinders use DTE Light and air mist. Looks like ceramic balls and phenolic
cages. 30K spindles. 3HP or so.

Wes


ayup

Ceramic bearings are getting more and more useage as the technology
improves

Gunner

"They couldn't hit an elephant at this dist..."
Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania

Thanks for the suggestion. As most things, there appear to be various grades
of Mobile's DTE oils, and I'll spend some time looking into Light and the
others.

Yep, the balls want to hydroplane, but there's nowhere to go.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Gunner Asch" wrote in message
...
On Sun, 21 Dec 2008 23:38:22 -0500, "Wild_Bill"
wrote:

I know there are some folks here that have considerable experience with
high
speed parts and lubricating oils.
I anyone has recommendations for oils with properties suitable for high
speed bearings, I'd appreciate hearing them.

The spindle speeds in toolpost grinders can range from about 6k to 30k
RPM.

I haven't taken them apart to see exactly what types of bearings are used
in
the spindles, but I would expect them to be high precision ball bearing
assemblies. I've seen parts list prices of over $200 each for bearings
with
ODs of about 1.25".

I presently have two brands, Themac 1/2 HP and Dumore 1/4 HP.


At those speeds, most bearings will be running with air/oil misting and
a very light turbine oil such as DTE Light

Cavitation becomes a real problem at high speeds in oil baths, as does
the fact that oil isnt a compressible and too much tends to make the
balls in the race ride up and over the oil droplets, slamming back down
on the other side.

The same effect that makes potholes on the back side of speed bumps.

Gunner

"They couldn't hit an elephant at this dist..."
Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of
Spotsylvania

Thanks for the technical info, Ned. Those numbers help to put things into
perspective.

I think those numbers were intended to apply to quality bearings, and not
many varieties of the dirt-cheap versions.

I suppose that a portion of the $200 bearing price would be for individual
human inspection and selection of the bearing assemblies, and possibly
related to a certain number of rejects that don't make the grade.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Ned Simmons" wrote in message
...
On Sun, 21 Dec 2008 23:38:22 -0500, "Wild_Bill"
wrote:

The spindle speeds in toolpost grinders can range from about 6k to 30k
RPM.

I haven't taken them apart to see exactly what types of bearings are used
in
the spindles, but I would expect them to be high precision ball bearing
assemblies. I've seen parts list prices of over $200 each for bearings
with
ODs of about 1.25".

A $6 6001 (12 x 28mm) bearing is rated for 26KRPM grease lubed and 32K
in oil. Oil mist or oil spot lube will probably push that to 45K. But
the devil is in the details of the spindle's construction at those
speeds. What you get with a $200 bearing is not necessarily higher
speed, but closer tolerances on the bearing's dimensions and running
accuracy.

--
Ned Simmons

Thanks again, Steve. Yep, I would expect any slight problem to relate
directly to the performance and the overall quality of the finish.

I was reading the earlier posts on balancing, and was surprised to learn of
the number of effects of balancing for different characteristics, and the
effects of those procedures on different speed ranges.

I don't know if I'll use these grinders on lathes, or maybe just apply them
to dedicated small parts grinding setups.

I don't do any machine operations that require any level of high precision,
but if I were to do some tooling grinding it may involve finishing of an
arbor taper, cutter sharpening or resizing small hardened parts.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Steve Lusardi" wrote in message
...
Bill,
If the spindle assembly is not up to snuff, you see harmonic patterns in
the finish. I think it's cheaper to leave it to the experts to sort out.
My last experience was with a small unit that I bought used. It looked
like new, but when I tested it, there was an inperceptable vibration and
this could be seen in the finish. When I sent it back, I was told that
there had been an engineering change in the design, which they applied to
my unit at the same time. If I had had not sent it back, I would not of
known. It now works perfectly.
Steve

"Wild_Bill" wrote in message
...
Thanks Steve, I didn't notice any Dumore models that weren't serviceable
(in looking thru their various models), but I did see their
recommendation to return their motors for servicing.

These grinder's parts would need to be made up of specialized parts for
the speeds they operate at, and I'd suppose that many used ones don't
operate as well as they were intended to.

--

On Wed, 24 Dec 2008 08:17:58 -0500, "Wild_Bill"
wrote:

Thanks for the technical info, Ned. Those numbers help to put things into
perspective.

I think those numbers were intended to apply to quality bearings, and not
many varieties of the dirt-cheap versions.

The numbers come from SKF. I didn't check, but I imagine
recommendations from other major mfrs would be similar. The $6 I
mentioned will get you an SKF, NSK, etc., bearing. A remarkable
bargain all things considered. But, yeah, I'd be reluctant to install
no-name bearings in any critical app to save $2.


I suppose that a portion of the $200 bearing price would be for individual
human inspection and selection of the bearing assemblies, and possibly
related to a certain number of rejects that don't make the grade.

I'm sure that's a big part of the price. That $6 bearing is quite
likely to come very close to, or even meet, the specs of the $200
bearing. But it doesn't come with the guarantee that it will.

--
Ned Simmons